controlador midi

Hello!!! I am new to arduino, and I am trying to build a midi controller and I would like to know:
1 Is it feasible to arm a controller with about 20 faders and about 80 buttons only with arduino UNO using multiple multiplexers?
2 Start testing with only 4 buttons, using the MIDI_Controller_v1 library, but when connecting 4 buttons in a 74hc4067 multiplexer, all 4 respond the same, as if they all had the same button.
Any help I may receive, I will appreciate it.


Do post complete schematic (you posted only some image of your part - that's not even a start of a schematic) and your code (the proper way - as per the sticky - which you should have read but seemingly didn't).

Short answer to 1.: yes.